Mold for septic tanks



March 31, 1931. E. J. HALL 1,798,670

MOLD FOR SEPTIC TANKS Filed Sept. 25, 1928 5 N II M 4 9M A I K .9 g

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attoznmp awuento'a Patented Mar. 31, 1931 PATEVNTY OFFICE ELVIN J. HALL, OF POMONA, CALIFORNIA MOLD FOR SEPTIC TANKS Application filed September 25, 192.8.

This invention relates to a mold adapted to be used when forming a septic tank. Vhen building a septic tank a pit or hole is dug in the ground and the bottom and walls of the pit are lined with concrete or cement in order to form the tank and this tank must be of the proper dimensions according to the number p of persons which the tank is to accommodate.

Therefore, one object of the invention is to In provide a mold including sections which when assembled in a pit dug in the ground may be adjusted to form a tank of the proper size.

Another object of the invention is to provide a mold consisting of sheet metal sections which may be securely but releasably connected by bridging plates serving to bridge the space between adjacent ends of companion wall portions, the plates being easily removable so that the mold may be taken apart and preserved for future use when building other tanks.

The invention is illustrated in the accompanying drawings, wherein Figure 1 is a perspective view showing the improved mold set in place within a pit dug in the ground.

Figure 2 is a vertical transverse sectional view taken through the mold along the line 22 of Figure 1.

Figure 3 is a fragmentary sectional view taken through a wall of the mold along the line 33 of Figure 1.

The improved mold constituting the sub ject matter of this invention is employed when building a septic tank and is to be set into a pit dug in the ground as shown in Figure 1, and indicated by the numeral 1. This pit, after being dug, has its bottom lined with cement or concrete and the mold may be assembled within the pit or externally thereof and lowered into the pit. The assembled mold is of such dimensions that its walls are disposed in spaced relation to the walls of the pit and the space between the walls of the pit and the mold are to be filled with con- Serial No. 308,258.

crete which, when set, will form the side and end walls of the septic tank. A septic tank has an inlet at one end and an outlet at its other end and, therefore, the mold must have its end walls so formed that pipes to provide an inlet and an outlet may be set in place when forming the walls of the tank.

This mold is formed of sheet metal of suffici'ent thickness to prevent danger of the mold being bent out of shape when in use and includes corner sections indicated in general by the numeral 2; Each corner section consists of a large metal sheet bent vertically intermediate its ends to form wall sections 3 and 4 which cooperate to form corner por- 6O tions of the mold, the portions 3 forming the end walls o fthe mold and the portions 4 cooperating to form its side walls. The sheets from which the corner sections are formed are of sufiicient height to form a tank having walls of the necessary depth and the wall portions 3 and 4 are of such length that when the mold is assembled with the side edges of the wall portions contacting, a septic tank of the smallest practicable capacity may be formed.

It should be noted that the wall portions 3 which cooperate to form the end walls of] the, mold are recessed from their free side edges so that when the mold is assembled 7 these recesses will define openings 5 through which pipes constituting an inlet and anoutlet for the septic tank may project and there by allow the end walls to be formed with the inlet and outlet pipes passing through them. so

In order to con-nect the companion wall portions 4 there has been provided plates 6 whichextend the full depth of these walls and in order to connect the wall sections 3 there has been provided plates 7 which extend from theirlower edges to the openings 5 and upper plates or strips 8 which extend across. the end walls above the openingsformed therein. These plates 6, 7 and 8 are formed with openings 9" spaced from each 90 turning in the openlngs.

other transversely of the plates and adapted to receive bolts 10 carried by the Wall sections and spaced vertically from each other adjacent their free side edges. The bolts are passed through openings 11 formed in the wall sections with their heads 12 countersunk into the walls and after the bolts are in place their heads are covered by solder or the like 13 as shown in Figure 3, so that the bolts will be firmly held in place and prevented from By passing the bolts through selected openings 9 of the plates the cooperating wall sections may be retained in determined spaced relation to each other with the plates bridging'th'e space between their free edges and a mold of the proper length and width for a septic tank of a determined capacity formed. Wing nuts 14- are employed to firmly secure the plates upon the bolts and they may be easily removed when it is desired to take the mold apart after the walls of a tank have been formed. The strips 15 Which are secured to the wall sections 4 in order to form grooves in the walls of a tank to receive bafile plates, may be removably secured so that they may be taken off in case it is desired to form a tank of a type in which baffle plates are not necessary. when the plates are removed the sections 2 will be released and can be easily removed from a formed tank.

WV hat is claimed is:

l. A mold for use in. constructing a septic tank of concrete, the same including forming walls, one of the walls being divided vertically toprovide sections and having portions out from the confronting vertical edges of said sections to define a pipe opening when the sections are assembled, a transversely disposed main bridging plate placed against the sections and connected thereto, and a com-v plemental bridging plate arranged trans.- versely of the wall sections and connected thereto, the confronting edges of the bridg' ing plates lying upon opposite sides of a straight line coinciding with the diameter of the said pipe opening and having portions cut therefrom to register with-the said pipe opening.

2. A mold for use in constructinga septic tank of concrete, the same including forming walls of sectional formation, and strips attached to certain sections and extending upwardly beyond the top edgesv thereof to admit of convenient removal of the walls after the concrete has set, said strips also serving to provide grooves in the walls of the tankto receive baflles.

3. A mold for forming a septic tank of concrete, comprising four corner members, each member consisting of a metal sheet bent intermediate its ends to provide right angularly disposed wall sections, the confronting vertical edges of the end Wall sections having portions cut away to provide pipe open- ELVIN J. HALL. 1,. s.] 

